Theories of delusional disorders. An update and review

Fusion of Clinical and Lived Experiences of Psychosis: Lessons Learned and Implications for Future Clinical Teaching

Psychosis is a clinical syndrome that can cause significant distress leading to hospitalisation/long term stays in psychiatric services. However, limited academic evidence is available examining the lived experience of psychosis. Additionally, no evidence is available looking to combine both learned and experiential knowledge as it pertains to psychosis. As such this article was created to combine both knowledge subsets in order to provide a more complete interpretation of the syndrome itself. This was achieved through academic input from a psychiatrist’s perspective as well as a reflective, autoethnographic input from a service user who has experienced psychosis. Following this collaboration, several recommendations were made to support health professionals to engage appropriately with service users with psychosis. However, the lived experiences of psychosis itself requires further investigation to identify commonalities in experiences that can support clinicians in the diagnosis and co-production of treatment regimens for these service users.

Cotard's Syndrome Triggered by Fear in a Patient with Intellectual Disability: Causal or Casual Link?

Cotard's syndrome is a neuropsychiatric disease characterized by a variety of nihilistic delusions, commonly associated with several psychotic and major affective disorders, and neurological diseases, including stroke, dementia, and mental retardation. A 39-year-old male with mental retardation developed Cotard's syndrome, following an important episode of fear. During admission to our neurological unit, the patient underwent an accurate assessment, including neuroradiological, clinical, and neuropsychological examinations. At the psychiatric evaluation, he presented nihilistic delusions, in which he negated the existence of his body parts and the existence of his family members. The neuropsychological assessment ruled out other possible causes of misidentification, including the post-traumatic stress disorder. Thus, since also organic causes of Cotard's syndrome were excluded, the correlation between fear and the syndrome has been postulated and the patient opportunely treated, using a multidisciplinary approach. Our case suggests that in predisposed individuals negative emotions, including fear, may lead to delusional syndromes.

Regional gray matter volume and structural network strength in somatic vs. non-somatic delusional disorders

BACKGROUND

Monothematic delusional disorders are characterized by a single tenacious belief. They provide a great opportunity to study underlying brain structures in the absence of confounding symptoms that accompany delusions in schizophrenia. Delusional beliefs include persecution, jealousy or somatic delusions including infestation. It is unclear whether specific delusional content is associated with distinct neural substrates.

METHODS

We used magnetic resonance imaging in patients presenting with somatic vs. non-somatic delusional disorders. Patients with delusional infestation (DI, n=18), and individuals with non-somatic delusional disorders (n=19) were included, together with healthy volunteers (n=20). Uni- and multivariate techniques for structural data analysis were applied to provide a comprehensive characterization of abnormal brain volume at both the regional and neural network level.

RESULTS

Patients with DI showed lower gray matter volume in thalamic, striatal (putamen), insular and medial prefrontal brain regions in contrast to non-somatic delusional disorders and healthy controls. Importantly, these differences were consistently detected at regional and network level. Compared to healthy controls, patients with delusional disorders other than DI showed lower gray matter volume in temporal cortical regions.

CONCLUSION

The data support the notion that dysfunctional somatosensory and peripersonal networks could mediate somatic delusions in patients with DI in contrast to delusional disorders without somatic content. The data also suggest putative content-specific neural signatures in delusional disorders and in delusion formation per se.

[Is delusion a reasonable scientific term? Reflections on psychopathology in the psychiatry of the twenty-first century]

Delusion is a central but difficult and controversial term in psychiatry. Similar to the term schizophrenia at the nosological level, the basic questions in the specialty are linked in the debate on delusion at the clinical psychopathological level, beginning with epistemological and methodological aspects up to concrete embodiment of the physician-patient relationship. The text of this article reflects this development from the nineteenth century up to the present day and makes reference to the lively discussion on the future directions of psychiatric research triggered by the research domain criteria (RDoC). Under certain prerequisites, including in particular an extensive understanding of psychopathology, delusion is considered to be a reasonable scientific term, also in the future.

Delusional disorder as a partial psychosis

In his textbook from 1838, Esquirol made the first comprehensive psychopathological description of paranoia, which he labeled partial psychosis. This was a condition with encapsulated, well organized, and persistent delusions. These are defended with a great deal of emotions and sharp argument. The individual appears quite convincing, especially because he or she otherwise behaves rationally. The intellectual capacity is used to achieve defined goals according to the delusional content. This condition is difficult to uncover because of dissimulation and adaptation. The frequency in the population is unknown, but the condition is rare in psychiatric treatment facilities, and usually only when the persons become litigious or criminal. In Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, the condition is covered by the concept of delusional disorder, but that concept also comprises benign acute/subacute conditions as well as cases that turn out to have the diagnosis changed to schizophrenia.

Deficits in executive and memory processes in delusional disorder: a case-control study

OBJECTIVE

Delusional disorder has been traditionally considered a psychotic syndrome that does not evolve to cognitive deterioration. However, to date, very little empirical research has been done to explore cognitive executive components and memory processes in Delusional Disorder patients. This study will investigate whether patients with delusional disorder are intact in both executive function components (such as flexibility, impulsivity and updating components) and memory processes (such as immediate, short term and long term recall, learning and recognition).

METHODS

A large sample of patients with delusional disorder (n = 86) and a group of healthy controls (n = 343) were compared with regard to their performance in a broad battery of neuropsychological tests including Trail Making Test, Wisconsin Card Sorting Test, Colour-Word Stroop Test, and Complutense Verbal Learning Test (TAVEC).

RESULTS

When compared to controls, cases of delusional disorder showed a significantly poorer performance in most cognitive tests. Thus, we demonstrate deficits in flexibility, impulsivity and updating components of executive functions as well as in memory processes. These findings held significant after taking into account sex, age, educational level and premorbid IQ.

CONCLUSIONS

Our results do not support the traditional notion of patients with delusional disorder being cognitively intact.

Neuropsychological research in delusional disorder: a comprehensive review

In recent decades, there has been a growing interest in the field of delusions, and different aspects of delusional disorder (DD) have been investigated. However, DD is still one of the most underresearched psychiatric disorders. In this paper, we review the literature on DD and most of the theoretical approaches proposed to explain the development and maintenance of delusions. DD research is infrequent, and delusions in this disorder have been scarcely investigated. We aim to establish the state of the art of delusions research to date and point to the shortage of neuropsychological studies in patients with DD. We also justify the need for future research into the neuropsychological correlates of DD as measured in patients with this disorder given that most previous research has mainly focused on other psychotic conditions.

Cortical mechanisms of the symptomatology in major depressive disorder: a resting EEG study

BACKGROUND

Diagnosis and treatment rely on symptom criteria in modern psychiatry. However, the cortical mechanisms of symptomatology in major depressive disorder (MDD) are still not clear. This study examined neural correlates of symptom clusters of MDD by electroencephalography (EEG).

METHODS

Resting state eye-closed EEG signals were recorded in 196 depressive patients. Quantitative EEG (qEEG) of regional power, coherence and power series correlation across delta, theta, alpha and beta frequencies were used to correlate with overall depression severity evaluated by the Hamilton Depression Rating Scale (HDRS). Further, statistical comparisons between patients with high vs. low qEEG indices (median-split) were undertaken regarding symptom severity of core depression, sleep, activity, psychic anxiety, somatic anxiety, and delusion.

RESULTS

None of the qEEG indices significantly correlated with overall depression severity or differentiated symptom severity of core depression, sleep, activity and psychic anxiety. A higher symptom severity of somatic anxiety was associated with higher regional power over widespread cortical regions and lower strengths at bi-temporal, temporo-parietal and fronto-parietal connections. A higher symptom severity of delusion was associated with higher regional power in the frontal and temporal regions, and lower strengths at inter-hemispheric (frontal, temporal and parietal) and fronto-temporo-parietal connections.

LIMITATIONS

Our EEG recording with sampling rate of 128Hz and 20 electrodes may provide restricted spatial and temporal precision.

CONCLUSIONS

Our results suggest that cortical mechanisms play important roles in the symptom manifestation of cognitive distortion (sub-score of delusion) and somatic anxiety in MDD. Our findings further imply that psychic anxiety and somatic anxiety are distinct entities.

A general neuropsychological model of delusion

INTRODUCTION

Neurocognitive accounts of delusion have traditionally highlighted perceptual misrepresentation, as the primary trigger in addition to other cognitive deficits that maintain the delusion. Here, a general neurocognitive model of delusional disorder (DSM-IV) is proposed, not so much based on perceptual or cognitive deficits after right hemisphere damage as on cognitive propensities, specifically excessive inferencing (especially jumping to conclusions) and excessive reference to the self, due to left hemisphere overactivity.

METHOD

The functional imaging, topographic EEG, and experimental imaging literatures on delusional disorder are reviewed, and 37 previously published cases of postunilateral lesion delusion (DSM-IV type, grandeur, persecution, jealousy, erotomania, or somatic), are reviewed and analysed multivariately.

RESULTS

Functional imaging and EEG topography data were slightly more indicative of left hemisphere overactivity in delusional disorder. In addition, 73% of the postunilateral lesion cases (χ(2)=7.8, p=.005) of delusional disorder (DSM-IV type) had a right hemisphere lesion, whereas only 27% had a left hemisphere lesion.

CONCLUSION

Left hemisphere release appears to be a more primary cause of delusional disorder than right hemisphere impairment, the latter merely entailing loss of inhibition of delusional beliefs. We propose that most patients with DSM-IV diagnoses of delusional disorder could be afflicted by excessive left hemisphere activity, but further research is necessary.

Differential effects of endogenous lithium on neurobehavioural functioning: a study on auditory evoked potentials

Lithium occurs naturally in food and water. Low environmental concentrations in drinking water are associated with mental illnesses and behavioural offences, and at therapeutic dosages it is used to treat psychiatric (especially affective) disorders, partly by facilitating serotonergic (5-HT) neurotransmission. As little is known about the psychophysiological role of nutritional lithium in the general population, endogenous lithium concentrations were hypothesised to be associated with measurable effects on emotional liability and the loudness dependence (LD) that is proposed as one of the most valid indicators of 5-HT neurotransmission. Auditory evoked potentials of healthy volunteers [N=36] with high (>2.5 microg/l) or low (<1.5 microg/l) lithium serum concentrations were recorded. Emotional liability was assessed using the Brief Symptom Inventory (BSI). Low-lithium levels correlated with Somatisation while correlations between lithium and LD were not significant. Still, LD correlated positively with Paranoid Ideation, negatively with Anxiety and, in the high-lithium group, inversely with further aspects of emotional liability (Depression, Psychological Distress). In conclusion, the effects of low levels of endogenous lithium are associated with emotional liability, and high levels with some protective effects, although findings remain inconclusive regarding LD. Potential benefits of endogenous lithium on neurobehavioural functioning, especially in high-risk individuals, would have public health implications.

The affective neuropsychology of confabulation and delusion

The paper reviews the history of the scientific understanding of the role of emotion in confabulation and delusion. I argue that the significance of emotion in the pathogenesis of these symptoms was obscured by academic polarisation between psychodynamic and neurocognitive traditions and was also often obfuscated by rigid distinctions between psychogenic and neurogenic explanations. This tradition of epistemic dualism was implicitly maintained in the fields of cognitive neuropsychology and cognitive neuropsychiatry. This paper focuses on memory-related confabulation following ventromedial frontal lobe lesions, awareness-related confabulation following right perisylvian lesions, and delusions of various aetiologies. Ambiguity regarding the definition and taxonomy of symptoms renders direct comparison difficult, but certain overriding principles are becoming discernible. Recent findings suggest that emotion and motivation influence both confabulation and delusion. These influences may be instigated directly by neural dysfunction or indirectly by life changes and altered social circumstances, or by a combination of these. Importantly, the rejection of epistemic dualism in the conceptualisation of both symptoms can allow us to study them in parallel and draw conclusions about the relation between cognition and emotion. Specifically, confabulation and delusion can be described as faulty attempts to balance the conflicting demands of accurate and self-serving reality representation.

Khantzian's 'self-medication hypothesis' of drug addiction and films by Martin Scorsese

The portrayal of self-medication and drug use was studied in three films by Martin Scorsese: Raging Bull (1980), Goodfellas (1990) and The Departed (2006). Self-medication using nicotine in Raging Bull, cocaine in Goodfellas and sedatives in The Departed, exhibit mixed portrayals of the self-medication hypothesis. The temporal aspects of the hypothesis and credibility of character psychopathology show variation between the films. Across all films, the selection of particular drugs of choice for certain symptom clusters is consonant with that detailed in the self-medication hypothesis put forward by Khantzian.